Refactor assets.
Add package collection.
Add class util.EnterFrameObserver.
Refactor package collection.
Rename lang.InvalidOperationException to lang.IllegalStateException.
Rename lang.InvalidOperationException to lang.IllegalStateException.
Refactor package collection.
Add package sound.
Global refactor.
Add class asset.ControlledSoundAsset.
Update pom.
Add new string utils.
Use logging in Asset. Refactor assets.
Add asset.SwfAsset.
Refactor asset.SwfAsset.
Refactor buttons.
Fix SwfAsset.
Refactor button.
Fix SwfAsset.
Fix SwfAsset.